In the toolchanger described in U.S. Pat. No. 3,803,704 of Seidel, and other similar toolchange mechanisms, it is very desirable to have a smooth, efficient, positive method for gripping the respective tools during an interchange. The grippers employed on the interchange arms of the aforementioned U.S. Patent grip the tools within a circumferential groove which is machined around a flange on the respective tool holders. The flange, which must be machined, creates additional overhang even in its minimal form; while the tool gripper must be made still smaller than the gripping groove so that the next succeeding tool may be passed across the grippers for its turn at being interchanged.
While the motions provided in the tool changer described are very smooth and successive in function, it is believed that the tool grippers and arm mechanism may be improved upon by gripping in an annular groove turned around the flange on the tool holder by a pair of "pincers" which will cause a more stable control of the tool holder during an interchange moment because of the opposing gripping surfaces on the diameter of the flange rather attempting to grip the part on one side of the flange only, as with the internal grip, thus allowing the tool holder to experience an instability.
Further, the majority of tool holders employed have keyways cut in their flange to provide a torque couple to a complementary key which is affixed to the spindle nose. On these type of tool holders it is most imperative that the keyway be closely controlled during its interchange path so that the spindle key may engage the keyway without interference.
Applicant believes that by using the existing output motions of the aforementioned U.S. Patent, his invention will provide a superior gripping device for tool holders and a simultaneous positioning device to orient the keyways of the tool holder while in transit.
It is therefore an object of the present invention to provide a tool interchange arm capable of imparting a high degree of stability to a tool holder when being automatically interchanged on a machine tool.
Another object of the present invention is to provide an orienting device which will cooperate smoothly with the tool gripping mechanism while in use, during transit, and which will automatically be retracted with the tool grippers when not in use.